Aayirathil Oruvan story begins with the two archaeologists Anitha (reema) and Lavanya (andrea) who work with the government and they set out on a mission with a team to Vietnam. In this, they are also accompanied by a set of coolies and they are led by Sukumaran (karthi). During their journey, they come across many twists and turns due to which the trio gets separated from the rest. Soon, they chance upon an ethnic Tamil group in the island and they are ruled by a king (parthiban). The tribes are living in poor conditions and just when the trio is captured to be killed, Anita reveals a secret. What happens after that forms the rest of the story.